A video demonstration on threads thru the hull presented by Forespar. ...read more

Video Transcript

And now for the exciting topic of threads on thru hulls.

On a marine thru hull- first of all a thru hull is just that. It is the fitting that goes through the hull and is secured or fastened on the inside with a nut or with a flanged valve called a seacock which replaces that nut.

It’s also important to note here that marine thru hulls all have parallel threads. No matter if they are US thread, BSB, or buttress- they are all parallel threaded. This is because no one ever knows the hull thickness that they are going to be installed on, so a taper would cause problems as the thru hull threads need to be cut to length for a given seacock installation or a valve installation.

This also means that the true marine seacocks or valves are also female parallel threaded to accept the thru hull. Non marine fittings and valves usually have NPT or nationally piped taper thread. This type is generally used in irrigation or house plumbing and should never be used below waterline. This is true of tail pipes and elbows on top of the valve as well. These connections must be sound and leak free. There is also more important information on threads on our website, forespar.com

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Why Marelon Plumbing Parts? (Video)

A video presentation on why Marelon plumbing parts are the best for your boat repairs ...read more

Video Transcript

Hi. I’m Wes Gary. I’ve built boats and I’ve been around sail and power boating for most my life. I’ve had my own plastics business for over 25 years and I’ve built a 55 foot slew. I know polymer composites very well.

I’m here today to talk about Forespars line of Marelon marine plumbing fittings. I know that Marelon is not just a plastic but an engineered carbon fiber and glass re-enforced composite polymer, ideally formulated for marine use. You go to your local boating supply store and you will notice that there are several plastic plumbing choices available. Marelon, however, is the only plastic to meet the rigorous marine UL test. Its also ISO certified and Marelon also meets the ABYC standards for above and below the waterline. These are the same tests that bronze or stainless steel parts have to pass too. I mention this because some of you may have seen Marelon fittings in stores and thought ot yourselves… ehhh… it’s a plastic and bronze has been the material of choice for boats in the past. Well think again.

What’s your boat made of? What about the hoses that are going to the valves? Well, if you accept those materials below the waterline, why not a valve that’s made from truly 21st century carbon fiber reinforced polymer composite.

There are other reasons as well. Marelon wil never corrode. Because it’s not made of anything metallic, it’s never subject to the cancer ravages of electrolysis. You don’t have to bond Marelon so you don’t have the additional copper bonding wires and you don’t’ have the additional potential corrosion of those as well, so all that goes away.

Marelon is also very lightweight. A typical bronze 1 1/2” seacock weighs about 10 pounds. A comparable Marelon 1 1/2” seacock weighs less than 2 pounds. Think about how more efficient you are going to be and how much more beer you can carry.

As you walk down the plumbing isle of your favorite marine hardware store, and you see the plastic stuff on the shelf, remember that all plastics are not created equal. Marelon is about as close as you can get to the material that your boat is made of in a precision melded, marine approved, polymer composite. It’s time to step out of the Bronze Age.